Laser marking is a marking technique that uses lasers and other forms of laser radiation to additively bond a marking substance to a wide range of substrates. Laser marking forms permanent marks on material such as metals, glass and ceramic parts, and is used in many applications, ranging from aerospace to awards and engraving industries. Laser marking differs from the more widely known techniques of laser engraving and laser ablation in that laser marking is an additive process, adding material to the substrate to form the marking instead of removing material as in those techniques.
Individual laser bonding/marking compositions have had limited success when used to mark different types of substrate materials, and are therefore classified according to the particular material to be marked. Instead, laser marking compositions are usually tailored for marking specific types of material. For example, a single laser marking composition may leave a satisfactory laser mark on stainless steel, but may leave an unsatisfactory mark on other materials such as different grades of aluminum, anodized aluminum, brass, copper, pewter, titanium, glass, ceramic, natural substances such as rock (e.g. slate) or paper products, and plastic. In order to mark on these other materials, different laser marking compositions have to be used than those used for marking stainless steel. Accordingly, there is a need for a high contrast laser marking composition that can be used for marking a variety of materials.